founded by south african entrepreneur elon musk, space-x has been a leader in the drive to develop commercial space travel. its company's dragon capsule is scheduled to orbit the earth four times next month, transmit data, receive commands, then re- enter the atmosphere and splash into the pacific ocean. if all goes as planned, it will deliver cargo and eventually astronauts to the international space station. and for more on all this, joining us now, our science correspondent miles o'brien. good to have you with us. >> good to be here. >> woodruff: let's talk background. the shuttle program going away. a lot of people don't realize it's not around for long. >> it's interesting. here we are approaching 30 years of shuttle flying, 130 some-odd flights and all good things, i guess, come to an end. this decision really was made on the heels on the loss of "columbia." in 2004, then president bush announced the slow retirement of the shuttle and the decision to move on to something else. at that time, the program was called "constellation" and the goal was return-to-return to the moon. but things